package com.king.sort;


/**
 * 堆排序
 */
public class HeapSort implements SortUtil.Sort {

	public void sort(int[] data) {
		MaxHeap h = new MaxHeap();
		h.init(data);
		for (int i = 0; i < data.length; i++)
			h.remove();
		System.arraycopy(h.queue, 1, data, 0, data.length);
	}


	private static class MaxHeap {


		void init(int[] data) {
			this.queue = new int[data.length + 1];
			for (int i = 0; i < data.length; i++) {
				queue[++size] = data[i];
				fixUp(size);
			}
		}

		private int size = 0;

		private int[] queue;

		public int get() {
			return queue[1];
		}

		public void remove() {
			SortUtil.swap(queue, 1, size--);
			fixDown(1);
		}

		//fixdown
		private void fixDown(int k) {
			int j;
			while ((j = k << 1) <= size) {
				if (j < size && queue[j] < queue[j + 1])
					j++;
				if (queue[k] > queue[j]) //不用交换
					break;
				SortUtil.swap(queue, j, k);
				k = j;
			}
		}

		private void fixUp(int k) {
			while (k > 1) {
				int j = k >> 1;
				if (queue[j] > queue[k])
					break;
				SortUtil.swap(queue, j, k);
				k = j;
			}
		}

	}

}